Location information erase on SIM cards

ABSTRACT

Methods and systems including non-transitory computer-readable storage media, for selectively erasing data stored at a wireless device are disclosed. The media include instructions that, when executed by a processor, cause the processor to perform a method including comparing a particular service provider identified by the data stored at the wireless device to at least one favored service provider selected from a group of favored service providers consisting of a home service provider and a preferred service provider other than the home service provider. The instructions further, when executed by a processor, cause the processor to erase, if the particular service provider is not one of the favored service providers, the data stored at the wireless device.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Provisional Application60/237,440, filed Oct. 3, 2000, and to U.S. patent application Ser. No.11/472,873 filed on Jun. 21, 2006, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to wireless networks and morespecifically to a system and method of erasing location information on aSIM card in a mobile telephone.

2. Discussion of Related Art

In a Global System for Mobile Communication (GSM) system, mobile phonesuse subscriber identifier modules (SIMs) associated with the mobilephone to store data. The SIM may be a check card or a plastic pieceabout 1 cm square that may be plugged into the mobile phone. The SIMenables a user to insert the SIM into any mobile phone and use thatphone with the user's account. Typically, the type of data storedincludes the personal identification number for the user, lists of theoptional functionality of the SIM, redial numbers, charges for timeincrements of phone use, subscriber data, secure data transmissionparameters, roaming data and public land mobile network (PLMN) data. Thepresent disclosure is directed to the use of the roaming data with itsassociated location information on the SIM card.

The SIM card is illustrated in FIG. 1. The wireless device 10 may be aGSM mobile phone or any other wireless device such as a personal digitalassistance or portable computer that uses a SIM card or a similarpermanent or detachable data card that functions like a SIM card tostore roaming data as described herein. The SIM card can be either asID-1 SIM 12 or a Plug-in SIM 14. The ID-1 SIM is a check card having amicrochip or a plug-in card 14 that is about 1 cm square. Thesedescriptions and dimension are not meant to be limited but only serve togenerally describe a SIM card. Most SIM cards have the same ability tobe inserted into a wireless device 10 such as a mobile phone and operateto provide parameters and data to operate the wireless device 10. Thewireless device 10 communicates through an air interface with a basestation 16 and an associated wireless network 18. The details of such anetwork are known to those of skill in the art, therefore, they are notdiscussed more herein.

The PLMN data include the network color code (NCC), which is athree-bit-long 10 code that identifies the PLMN. The NCC is part of theBSIC and is broadcast in the synchronization channel. Other PLMNparameters include the mobile country code (MCC), which is a three-digitidentifier that uniquely identifies a country (not a PLMN) and themobile network code (MNC) of the home PLMN.

The roaming data includes location updating status parameters fordetermining whether to update the location data, location areainformation (LAI), and the NCC of preferred PLMNs. The roaming data alsoincludes a list of preferred PLMNs or service providers that the mobilephone should select if more than one service provider is available andthe home PLMN is not found

When a GSM mobile phone is powered on, the mobile phone needs to selecta service provider. The current PLMN service provider is stored on theSIM card as part of the location information. The mobile phone checksthe stored service provider in the location information upon power upbefore looking for the home service provider or another preferredservice provider. If the mobile device finds a service provider usingthe PLMN service provider stored in the location information on the SIM,it will use that service provider.

The approach of first searching at power up for a service provider usingthe service provider stored on the SIM card causes several problems.First, suppose the user's previous use of the mobile phone was with aroaming service provider outside of the home-use area and the next powerup by the user is in his or her home PLMN. In this scenario, if theroaming service provider also provides service in the home service areaof the mobile user, the mobile phone may register with the roamingservice provider when it should register with the user's home serviceprovider.

Second, as discussed above, part of the roaming data includes the NCCsof preferred PLMNs with which the mobile phone should register if thehome PLMN is not available. If the user is roaming outside his or herhome service area, and another more preferred service provider is listedin the roaming data, the mobile phone may still attain service from theservice provider listed as the current service provider in the locationinformation although that service provider is lower down or not even onthe preferred service provider list.

Accordingly, for the foregoing reasons, there are drawbacks to thepresent system and method of searching for a service provider when a GSMmobile phone is powered up.

SUMMARY OF THE INVENTION

In order to address the deficiencies of the related art, the presentinvention is proposed for erasing the location information on SIM cards.The process of erasing the location information may occur on power up orduring the power down routine, or under other circumstances. Forexample, a comparison may be made between the service provider stored inthe location information and the horns service provider or a preferredservice provider, if the home service provider or a preferred serviceprovider is the service provider stored in the location information,then the location information would not be erased.

The present invention may take the form of a mobile phone, SIM card,method or medium storing a program for operating a series of steps forerasing part or all of the location information on a SIM card. Anadvantage of the present invention is to enable service providers tohave some control in the service provider search routine.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing advantages of the present invention will be apparent fromthe following detailed description of several embodiments of theinvention with reference to the corresponding accompanying drawings, inwhich:

FIG. 1 illustrates a SIM card associated with a GSM mobile phone;

FIG. 2 illustrates a wireless device with a SIM card installed;

FIG. 3 illustrates a power up routine for erasing location informationon a SIM card;

FIG. 4 illustrates power down routine for erasing location informationon a SIM card; and

FIG. 5 illustrates a routine to selectively erase location informationon a SIM card.

DETAILED DESCRIPTION OF THE INVENTION

The present invention may be understood with reference to the drawings.First, we turn to FIG. 2, which illustrates a wireless device 50 for usewith the present invention. The wireless device 50 comprises a receivingslot 20 for a SIM card 22. The 25 SIM card communicates with wirelessdevice circuitry 24 that includes a central processor, clock and tone,internal bus system and keyboard control. In addition, the wirelessdevice includes a microphone 40, voice encoder 24, channel encoding,interleaving and burst generation circuitry 26, a ciphering module 28, amodulation unit 30, and an amplification unit 32. The signal is thentransmitted to a base station (not shown) via an antenna 42. The antenna42 also receives signals and uses a demodulator 40, deciphering unit 30,channel decoder, de-interleaver and re-formatting unit 36, and a voicedecoding unit 34 to prepare received signals to provide to the userthrough a speaker 44. The system and method of the present invention maybe programmed into the SIM card 22, programmed into the wireless device50, provided via a recorded medium, or transmitted from a wirelessnetwork 15, for example, as shown in FIG. 1.

The specific hardware components as shown is FIG. 2 are not critical forthe present invention. Any arrangement of internal components of awireless device 50 may be used. The more important aspect of theinvention is the operation of the hardware components to erase theinformation on the SIM card or on a similar component.

The present invention comprises different aspects of erasing locationinformation from either the SIM 22 or other memory associated with thewireless device 50 in order to modify the first service provider thewireless device searches for on power up. The SIM 22 may have a firstmemory module and a second memory module for storing the various datanecessary for its operation. It may further have other memory modules orstorage locations for the various parameters, data or executableprograms for operating routines according to the present invention. Thelocation information may be any information associated with the mostrecent service provider used by the wireless device. Accordingly, thedisclosure herein is not limited to the kind of location informationnormally associated with GSM networks.

In one aspect of the invention, the program that operates to eraselocation information may be stored on a recording medium associated withthe use of a wireless device. Such a recording medium would comprisefirst memory that stores data associated with location information, andsecond memory that stores a program executable to erase at least some ofthe data associated with a most recently used service provider. Thefirst memory of the recording medium may further store data associatedwith a home service provider, a preferred service provider or a list ofpreferred service providers. The recording medium may also include thesecond memory that stores a program that erases at least some of thedata when the most recently wed service provider is not the home serviceprovider or the preferred service provider. Such a recording medium maybe a compact disk, floppy disk, computer chip, or other electronicrecording means for storing a data erase routine according to thevarious aspects of the invention disclosed herein.

FIG. 3 shows a flow chart according to an embodiment of the invention.This aspect of the invention relates to the process occurring in thepower up routine of the wireless device 60. According to this aspect ofthe invention, the power up routine begins (100) either by the userpressing the on button or some other means. During the power up routine,before the wireless device 60 begins looking for a service provider, theprocess involves erasing at least a portion of the location information(102) on the SIM. The location information includes at least in part thepresent or most recently used service provider.

Next, the routine chooses a service provider (104) by first looking tothe location information for the most recently used service provider.Since the service provider listed in the location information has boonerased, the routine next chooses a service provider (104) from the homeservice provider or a preferred service provider listed in the roamingdata. In this manner, the home service provider may enhance its abilityto direct its subscribers to particular roaming service providers.

FIG. 4 illustrates another aspect of the present invention in which atleast some of the location information is erased during power off. Asshown, as the power off routine begins (110), the process involveserasing at least some of the location information (112). After thelocation information is erased, the power off routine is completed(114). As the normal power up routine (116) executes on the next powerup, the routine chooses a service provider (118) by searching for aservice provider in the location information in the SIM. However, noservice provider will be listed so the power up routine proceeds tosearch for either the home service provider or a preferred serviceprovider.

FIG. 5 illustrates another aspect of the present invention wherein thelocation information is selectively erased. In this process, either thepower on or power off procedure begins (130). The routine compares theservice provider stored in the location information with the homeservice provider and/or the list of preferred service providers in theroaming data (132). The comparison determines whether the serviceprovider stored in the location information is the home service provideror one of the preferred service providers.

If the location information is not the home service provider or one ofthe preferred service providers, then at least some of the locationinformation is erased (134). Then, the routine chooses the serviceprovider according to its program (136). If step 130 involves theprocess shown in FIG. 5 being operated during a power off routine, thenclearly step 136 is performed on the next power on routine executed bythe user.

There are further variations to the routine outlined in FIG. 5. Forexample, when comparing the location information service provider to thehome service provider and preferred service providers, a threshold valuemay be determined for the preferred service providers. In this case,suppose a list of four preferred service providers exists. Step 132 mayinvolve determining whether the location information service provider iseither the home service provider or one of the first two preferredservice providers of the four listed preferred service providers. Inthat case, if the location information service provider is not the homeor one of the first two preferred service providers, then the locationinformation is erased (even though the location information serviceprovider may be one of the third or fourth listed preferred serviceprovider).

Furthermore, step 132 in FIG. 5 may also be modified to check only ifthe location information service provider is the home service provider,and if it isn't, then step 132 will erase the location information. Theeffect of the various aspects of the present invention is to use theconcept of erasing the location information fully or in part to takeadvantage of the service provider search routine of the wireless device.In this manner, the wireless device can be directed more efficiently toan acceptable service to provider. Thus, there may be other aspects ofthe invention not disclosed or discussed here involving ways of erasingthe location information or other stored service provider information totake advantage of the service provider search routines. Any and all suchmodifications of this basic idea are considered as within the scope ofthe present disclosure.

Although the above description may contain specific details, they shouldnot be construed as limiting the claims in any way. Other configurationsof the described embodiments of the invention are part of the scope ofthis invention. For example, many of the embodiments are disclosed asbeing associated with the GSM system and SIM cards. However, otherwireless networks with various wireless devices may also store thecurrent or most recent service provider in a memory unit. The presentinvention therefore may be applicable to any device that searches for aservice provider in generally the same manner as is described herein.Furthermore, any functional language provided herein is only meant todescribe how the invention may work and is not meant to limit the claimsor be used as substitute function in a doctrine of equivalents analysis.Accordingly, the appended claims and their legal equivalents should onlydefine the invention, rather than any specific examples given.

What is claimed is:
 1. A system, for use in organizing a search for aservice provider, comprising: a processor; and a computer-readablestorage medium comprising computer executable instructions that, whenexecuted by the processor, cause the processor to perform operationscomprising: comparing, at power down of a wireless device, locationinformation associated with a particular service provider to dataassociated with a home service provider and data associated with apreferred service provider; and erasing, in response to a determinationthat the particular service provider is not the home service providerand is not the preferred service provider, at least part of the locationinformation.
 2. The system of claim 1, wherein the operations furthercomprise determining, based on the comparing, whether the particularservice provider is the home service provider or is the preferredservice provider.
 3. The system of claim 1, wherein erasing at leastpart of the location information further comprises erasing locationinformation associated with a most-recently-used service provider. 4.The system of claim 1, wherein the wireless device is aglobal-system-for-mobile communications device.
 5. The system of claim4, wherein the wireless device has a subscriber identity module.
 6. Thesystem of claim 5, wherein erasing at least part of the locationinformation further comprises erasing location information from thesubscriber identity module.
 7. The system of claim 5, wherein erasing atleast part of the location information further comprises erasing all ofthe location information from the subscriber identity module.
 8. Thesystem of claim 5, wherein: the computer-readable storage mediumincludes the subscriber identify module comprising a program; anderasing at least part of the location information is performed by theprocessor executing the program stored on the subscriber identitymodule.
 9. The system of claim 1, wherein erasing at least part of thelocation information further comprises erasing location information froma subscriber identity module of the wireless device.
 10. The system ofclaim 1, wherein erasing at least part of the location informationfurther comprises erasing all of the location information stored at thewireless device.
 11. The system of claim 1, wherein erasing at leastpart of the location information is performed by the processor executinga program stored on the subscriber identity module.
 12. The system ofclaim 1, wherein: the system is part of a wireless network; and erasingat least part of the location information comprises the processor of thewireless network transmitting a signal to the wireless device toinitiate the erasing.
 13. The system of claim 1, wherein the operationsfurther comprise selecting, in response to a next power up of thewireless device, a service provider from a list comprising the homeservice provider and the preferred service provider.
 14. Acomputer-readable storage device comprising computer executableinstructions that, when executed by a processor, cause the processor toperform operations comprising: comparing, at power down of a wirelessdevice, location information associated with a particular serviceprovider to data associated with a home service provider and dataassociated with a preferred service provider; and erasing, in responseto a determination that the particular service provider is not the homeservice provider and is not the preferred service provider, at leastpart of the location information.
 15. A method, for use in organizing asearch for a service provider, comprising: comparing, by a systemcomprising and using a processor, at power down of a wireless device,location information associated with a particular service provider todata associated with a home service provider and data associated with apreferred service provider; and erasing, by the system, in response to adetermination that the particular service provider is not the homeservice provider and is not the preferred service provider, at leastpart of the location information.
 16. The method of claim 15, whereinerasing at least part of the location information further compriseserasing location information associated with a most-recently-usedservice provider.
 17. The method of claim 15, wherein erasing at leastpart of the location information further comprises erasing locationinformation from a subscriber identity module of the wireless device.18. The method of claim 15, wherein erasing at least part of thelocation Information is performed in execution of a program stored on asubscriber identity module installed at the wireless device.
 19. Themethod of claim 15, wherein: the computer-readable storage device ispart of a wireless network; and erasing at least part of the locationinformation comprises the processor of the wireless network transmittinga signal to the wireless device to initiate the erasing.
 20. The methodof claim 15, wherein the operations further comprise selecting, inresponse to a next power up of the wireless device, a service providerfrom a list comprising the home service provider and the preferredservice provider.